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Beachcomber OEM 3005820 spa filter (C-4401)
Beachcomber two-piece microfilter, generally pre-1995
Replacement numbers
Unicel C-4401, Pleatco PRB17.5SF-PAIR
Fits Beachcomber OEM 3005820.
Diameter 4-15/16" (125 mm)Length 4-5/8" (117 mm)35 sq ft1 model listedSearch this part on Amazon
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| Unicel | C-4401 |
|---|---|
| Pleatco | PRB17.5SF-PAIR (Unicel cross-reference PDF p.47: C-4401 = PRB17.5SF-JH-PAIR. Spec table PDF p.31: PRB17.5SF-PAIR is 5" x 4-5/8", 2-1/8" both ends, 35 sq ft; PRB17.5SF-JH-PAIR has a 2-3/16" bottom hole. No Beachcomber stock number.) |
| Filbur | FC-2386 |
| Top | 2-1/8" (54 mm) / open |
| Bottom | 2-1/8" (54 mm) / open |
Bottom: 2-1/8" (54 mm) / open
Drawn to scale from the listed diameter and length and open-end sizes. Handles, threads and closed ends are drawn as symbols, not to scale. 35 sq ft media.
For Beachcomber, C-4401 cartridge (SKU 3005820) sits in Beachcomber two-piece microfilter, generally pre-1995. The cross-reference prints OEM 3005820; Unicel C-4401; Pleatco PRB17.5SF-PAIR; Filbur FC-2386. 4-15/16" across, 4-5/8" long, top 2-1/8" / open, bottom 2-1/8" / open, 35 sq ft.
Catalog note for 3005820: Beachcomber sells SKU 3005820 as a two-piece 35 sq ft set for generally pre-1995 hot tubs with an upfront weir: the piece with the blue stem goes in first. The product page prints no diameter or length. Unicel and Filbur both size one cartridge at 4-15/16" x 4-5/8", open 2-1/8" ends, two per set. Unicel's spec note says two cartridges per set with a stick handle, 158 pleats, 4 oz. Pleatco prints PRB17.5SF-PAIR at 5" x 4-5/8".
C-4401 (OEM 3005820), Pleatco side: Unicel cross-reference PDF p.47: C-4401 = PRB17.5SF-JH-PAIR. Spec table PDF p.31: PRB17.5SF-PAIR is 5" x 4-5/8", 2-1/8" both ends, 35 sq ft; PRB17.5SF-JH-PAIR has a 2-3/16" bottom hole. No Beachcomber stock number..
3005820, Filbur note: Beachcomber Spas section, PDF p.15: FC-2386, 4-15/16" x 4-5/8", 2-1/8" open, Rainbow DSF 35, 2/set, PRB17.5SF-PAIR/JH, C-4401, 35 sq ft..
Hot tubs named for 3005820: Beachcomber hot tubs with the upfront weir, years generally pre-1995, listed by Beachcomber Hot Tubs product page (two-piece 35 sq ft set; also some older off-brand spas).
Hold C-4401 next to C-4405 differs by Unicel C-4405, Pleatco PRB25SF-PAIR, Filbur FC-2387, 6-5/8" long, 50 sq ft, OEM 3005825, note says Beachcomber's two-piece 50 sq ft set for the same generally pre-1995 upfront weir as SKU 3005820. The page says the 50 sq ft medium doubles filtration capacity and prints no length. Unicel and Filbur size it at 4-15/16" x 6-5/8", longer than the 35 sq ft pre-1995 cartridge, so it is not the same body with more pleats. Unicel counts 158 pleats and 4 oz, two per set. Pleatco prints PRB25SF-PAIR at 5" x 6-5/8".; C-4326 differs by Unicel C-4326, Pleatco PRB25-IN, Filbur FC-2375, 13-5/16" long, 25 sq ft, OEM 3005845, note says Beachcomber's 25 sq ft microfilter for hot tubs from 1995 to the present. Beachcomber and Unicel agree on 4-15/16" x 13-5/16", a 2-1/8" open core and 3 oz media. Beachcomber counts 107 pleats; Unicel's spec table counts 106 for C-4326. Unicel calls C-4950 an upgrade of this body. Pleatco prints PRB25-IN at 5" outside diameter and does not name Beachcomber..
Left blank on purpose: Beachcomber prints no length; Pleatco outside diameter is 5" and its JH-PAIR bottom hole is 2-3/16" rather than 2-1/8".
Where those figures are printed: Beachcomber Hot Tubs (manufacturer product page) on C-4401 (SKU 3005820: 35 sq ft, two pieces, blue stem installed first, generally pre-1995 upfront weir; no length printed). Unicel 2026 Replacement Guide on C-4401 (Beachcomber OEM cross-reference, PDF p.29 (printed p.25): 3005820 = C-4401, 4-15/16" x 4-5/8", 35 sq ft, 4 oz; spec table PDF p.8 (printed p.4): 158 pleats, 2-1/8" open, two per set with stick handle). Pleatco 2023 Catalog on C-4401 (Unicel-to-Pleatco cross reference, PDF p.47; spec table PDF p.31 (5" OD)). Filbur Catalog & Reference Guide on C-4401 (Beachcomber Spas, PDF p.15: FC-2386 = C-4401, 4-15/16" x 4-5/8", 2/set, 35 sq ft).
Hot tubs listed for this cartridge
The rest of the Beachcomber model list is the Beachcomber filter by model and year lookup.
| Model / system | Years | Listed by |
|---|---|---|
| Beachcomber hot tubs with the upfront weir (two-piece 35 sq ft set; also some older off-brand spas) | generally pre-1995 | Beachcomber Hot Tubs product page |
Check the cartridge you removed
Measure diameter, length, and both ends, then compare them with the figures above. The steps are in the measuring guide. Why the bottom decides whether it seals: open-end vs threaded filters. Power, the retainer, and not running the spa empty: how to install a cartridge. Number formats: how Filbur, Unicel and Pleatco numbers compare.
Other Beachcomber cartridges
- C-4405 cartridge (SKU 3005825), 4-15/16" (125 mm) × 6-5/8" (168 mm)
- C-4326 cartridge (SKU 3005845), 4-15/16" (125 mm) × 13-5/16" (338 mm)
- C-4950 cartridge (SKU 3005815), 4-15/16" (125 mm) × 13-5/16" (338 mm)
Every number on this row, on one screen: cross-reference lookup. Published clean and replace intervals for this cartridge, and a buy link for the numbers above: replacement schedule and reorder. The interval comparison by brand: calculator.
Cleaner and test strips
Hose rinse and soak steps are in how to clean a cartridge. Named cleaners and strips are in filter cleaners and test strips.
Filter cleaner and test strips
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Leisure Time O Filter Clean Cartridge Cleaner Listing title: cartridge cleaner, 32 fl oz.
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SpaGuard Filter Cleaner Listing title: filter cleaner for spas and hot tubs, 1 quart.
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AquaChek SPA 6-in-1 Test Strips Listing title: reads total bromine, total chlorine, free chlorine, pH, total alkalinity and total hardness.
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Sources
- Beachcomber Hot Tubs (manufacturer product page): SKU 3005820: 35 sq ft, two pieces, blue stem installed first, generally pre-1995 upfront weir; no length printed (web page)
- Unicel 2026 Replacement Guide: Beachcomber OEM cross-reference, PDF p.29 (printed p.25): 3005820 = C-4401, 4-15/16" x 4-5/8", 35 sq ft, 4 oz; spec table PDF p.8 (printed p.4): 158 pleats, 2-1/8" open, two per set with stick handle (PDF)
- Pleatco 2023 Catalog: Unicel-to-Pleatco cross reference, PDF p.47; spec table PDF p.31 (5" OD) (PDF)
- Filbur Catalog & Reference Guide: Beachcomber Spas, PDF p.15: FC-2386 = C-4401, 4-15/16" x 4-5/8", 2/set, 35 sq ft (PDF)
Not in sources: Beachcomber prints no length; Pleatco outside diameter is 5" and its JH-PAIR bottom hole is 2-3/16" rather than 2-1/8".